CORS (Cross Origin Resource Sharing) is a security mechanism used by web-browsers. It blocks a website from accessing the content of another website.

In this case, a web-based application cannot access the GraphQL Interface, unless the mandatory CORS headers are present in the server response.

Solution:

• Enter the necessary CORS entry in the zenon6.ini: 
  [GraphQlInterface]
  GRAPHQLINTERFACE_ALLOWED_CORS_ORIGINS=https://localhost:9090,https://DOMAIN.TLD 
  
  Hint: For "DOMAIN.TLD", enter the desired domain name and the top level domain.

To benefit from this fix:

• Upgrade to the latest build of zenon Software Platform 11 or later.